1. This slide contains information that may be useful to the presenter. The presentation is set up in to not show this slide during the presentation. (In the drop-down menu, the setup is found under “Slide Show”  “Set Up Show…”  “Show slides”) This module was prepared by Susan Bone, CELP. Please send comments or suggestions to celp@dal.ca This presentation is derived from Pollution Probe’s Primer on Climate Change and Human Health. 2004. ©, available for free downloading at http://www.pollutionprobe.org/Reports/climatechangeprimer.pdfcelp@dal.ca http://www.pollutionprobe.org/Reports/climatechangeprimer.pdf Basic PowerPoint Instructions: To edit slides and/or to view additional lecture notes go to “View” on the drop-down menu and select “Normal” Be sure to save after making changes To show the presentation go to “Slide Show” on the drop-down menu and select “View Show” To advance to the next slide press the right or up arrow, to go back press the left or down arrow To end the slide show press “Esc” in the upper-left-hand corner of your keyboard at anytime during the slide show

2. Climate Change & Human Health

3. Outline Introduction to climate change Climate change & human health

4. Global Warming There is international scientific agreement that the world is getting warmer Evidence from tree rings, tropical corals, & ice cores from Greenland tell us that the 20 th century was the warmest of the past 1000 yrs, and the 1990’s were the warmest decade ever recorded by modern climatologists

5. Global Temperature Change (1869 – 2002) (Relative to 1961 – 1990 average temperature)

6. Global Climate Ultimately, climate is regulated by how much energy is received from the sun & how much is radiated back to space Other factors affecting climate include: the atmosphere (specific gases & aerosols are important, as are cloud cover and winds) the oceans (help to distribute heat through currents) evaporation (cools surfaces, including vegetation) water (in the form of lakes & rivers, or as snow & ice) land cover (affecting reflection and absorption of solar energy)

7. The Natural Greenhouse Effect It occurs because some energy from the sun is absorbed, heating Earth’s surface, and resulting in the planet cooling itself by radiating long-wave infrared energy to outer space However, certain chemical compounds (greenhouse gases) in the atmosphere absorb some of the radiated infrared, trapping heat in the atmosphere, and keeping Earth’s temperature within a range suitable for life Earth has always had a natural greenhouse effect

8. The Natural Greenhouse Effect

9. The Anthropogenic Greenhouse Effect Human (or anthropogenic) activities have increased the concentrations of important atmospheric GHGs, affecting the amount of energy (heat) stored in the atmosphere e.g., increased concentrations of carbon dioxide (CO 2 ) will absorb some infrared radiated by Earth’s surface, causing the temperature of the lower atmosphere to increase

10. Global Warming vs. Climate Change Global Warming refers specifically to the increase in temperature of the Earth’s lower atmosphere as a result of the enhanced (i.e., anthropogenic) greenhouse effect Climate Change refers to the complex effects resulting from the warming, i.e., changes in precipitation, windstorms, and other aspects of weather and longer-term climate

11. Greenhouse Gases The atmospheric lifetime of GHGs varies, from 12 years (methane or CH 4 ) to 150 yrs (carbon dioxide or CO 2 ), to 50,000 yrs (freons and some other halocarbons) GHGs occur in the atmosphere in different concentrations CO 2 is the GHG whose increase in concentration has most increased because of human activities Most of the CO 2 has been released by burning carbon-containing fossil fuels and wood, and because of deforestation

12. Greenhouse Gases Each GHG has a specific capacity for trapping heat, known as its global warming potential (GWP) If CO 2 has a GWP of 1.0, then that of methane is 23, N 2 O is 300, and freons and related halocarbons are up to 22,000 In other words, methane can absorb infrared energy radiated by the planet 23 times more effectively than CO 2

13. The Main Greenhouse Gases Naturally occurring GHGs: water vapour (H 2 O) carbon dioxide (CO 2 ) methane (CH 4 ) nitrous oxide (N 2 O) ozone (O 3 ) Anthropogenic GHGs (a.k.a. halocarbons): chlorofluorocarbons (CFCs) hydrofluorocarbons (HFCs) perfluorocarbons (PFCs) sulfur hexafluoroide (SF 6 )

14. Percentage of GHG emissions by sector for Canada (1998) Emissions of GHGs

15. Climate Change & Human Health

16. According to a study by the World Health Organization, an estimated 150,000 deaths were caused by climate change in 2000 Climate change may affect human health: directly, e.g., temperature extremes resulting in illness or death, severe storm events causing injury or death) or indirectly by changes in environmental quality, e.g. by increasing smog, other air pollution, waterborne and food-related illnesses

17. Climate change will likely mean an increase in heat waves (> 3 days with air temp > 32 o C), and a decrease in cold temperature extremes Heat-related illnesses include cramps, fainting, heat exhaustion, and heatstroke A heat wave in 1995 in Chicago resulted in 765 heat-related deaths, mostly of elderly persons Children and elderly are at particular risk from heat-related illnesses, because they are less able to regulate body temperature Temperature Extremes & Health Risks

18. Extreme Weather Extreme weather refers to severe events, such as floods, droughts, forest fires, hurricanes, tornadoes, storm surges, and snow & ice storms Global warming speeds up the water cycle by putting more moisture in the atmosphere, which in turn causes more precipitation-driven events Sea level rise, resulting from thermal expansion of seawater and melting of glaciers, will lead to more devastating storm surges in coastal regions

19. Extreme Weather & Health Risks Weather and climate related disasters are estimated to cause 225,000 deaths/yr globally From 1985 to 1999, there were 380 weather-related natural disasters in Canada, resulting in 240 deaths Extreme weather can affect human health both directly and indirectly

20. Air Pollution & Health Risks The atmosphere is contaminated by both natural pollutants (e.g., pollen, emissions from forest fires) and pollutants from human activities (e.g., from automobiles, power plants, dry-cleaning operations) All of these potentially toxic substances contribute to smog and other kinds of air pollution Health affects include allergies, decreased lung function, cardio-respiratory disease, and premature death In Ontario in 2000, 1,925 premature deaths were attributed to smog Children, the elderly, people who exercise outside, and those with asthma are at elevated risk

21. Air Pollution & Climate Change Climate change could increase air pollution in many ways: 1.by affecting local weather (cloud cover, wind speed & direction), which affects how pollutants are dispersed & in what concentrations 2.by increasing natural emissions of air pollutants, e.g., by making wildfires more frequent 3.by increasing emissions of anthropogenic pollutants, e.g., if higher temperatures mean more energy is needed to run air conditioners 4.by changing the type and amount of airborne allergens, e.g., ragweed pollen

22. Water- & Food-borne Pathogens Water-borne diseases result from pathogens (disease-causing organisms) that spread through polluted drinking water Food-borne illnesses occur when harmful microorganisms (e.g., Salmonella and E. coli) occur in food because of polluted water or unsanitary conditions in slaughterhouses

23. Health Risks of Pathogens Pathogenic microbes in water can cause eye, ear, nose, skin, respiratory, & gastrointestinal infections, diarrhea, loose or watery stools, stomach cramps, and fever, sometimes leading to death In Canada, between 1974 and 1996, there were 160 reported outbreaks of water- borne diseases, involving 8000 people But it is estimated that only 10% of outbreaks in Canada are reported

24. Water- & Food-borne Contamination and Climate Change Climate change might increase the occurrence of these water- and food- borne diseases in several ways: 1.warmer temperatures enhance the growth of harmful bacteria and protozoa 2.heavy rain events may wash fecal pollutants from agricultural fields into subsurface water used for drinking 3.drought may cause fecal pollutants to become more concentrated in smaller volumes of water 4.warmth & drought encourage the growth of toxic algae in surface waters used for drinking

25. Important water- and/or food-borne pathogens that may become worse with climate change: 1. Cryptosporidium is a protozoan parasite that is excreted in feces and spread by drinking polluted water 2. Giardia is another pathogenic protozoan, also known as “beaver fever” 3. E. coli is a bacterium; most strains are harmless and live in the intestines of humans & animals, but others produce a powerful toxin (e.g., tragedy in Walkerton, ON in 2000) 4. Hepatitis-A (HAV) is a deadly virus

26. Vector-borne Diseases A vector is an animal (e.g., a rat, mosquito, or tick) that can pass an infectious disease to humans or to other animals Vector-borne diseases usually require three conditions: 1.an alternate human/animal “host” for the disease 2.a large population of the vectors 3.ecological conditions appropriate for the vector, including temperature

27. Vector-borne Health Risks Warmer temperatures may enable certain vectors to extend their range and abundance, increasing the likelihood of people contracting the diseases they carry Vectored diseases that may affect more Canadians because of climate warming: Lyme Disease (tick-borne) Rocky Mountain Spotted Fever (tick) West Nile Virus (mosquito) Malaria (mosquito) Leptospirosis (rodent) Hantavirus Pulmonary Syndrome (deer mouse)

28. Climate change may influence vector- borne diseases in several ways: warmer ambient temperature often means increased survival of bloodsucking insects during winter, resulting in larger populations in the spring diseases reproduce faster in vectors in warmer temperatures mosquito larvae develop into adults much quicker in warm weather, meaning faster generational turnover and more mosquitoes floods leave abundant standing water, providing breeding habitat for mosquitoes floods and warm weather can increase the food supply of rodents, influencing their population size and range

29. Weather and the Spread of the West Nile Virus in New York City, Summer 1999

30. Depletion of Stratospheric Ozone the atmosphere consists of several layers: the troposphere extends from the surface as high as 12 km the stratosphere occurs above the troposphere the “ozone layer” is a stratospheric region with high O 3 concentrations ─ it provides natural protection against biologically damaging ultra-violet radiation ozone depletion = the destruction of stratospheric O 3 by CFC and HCFC gases released from air conditioners & aerosol cans

31. Regions of the Atmosphere

32. Health Risks of Ozone Depletion intense exposure to UV increases the risk of damage to DNA, potentially causing eye damage and skin cancers UV-B radiation is particularly linked to skin cancers, including deadly melanoma melanoma killed 840 Canadians in 2003 characteristics of individuals particularly at risk: fair skin & hair, light-coloured eyes, moles, freckles, or birthmarks spend much time outdoors, live in polar regions, or have a family history of skin cancers

33. UV Radiation In general, the shorter the wavelength of the UV radiation, the more biologically damaging it can be. UV-C wavelengths are the shortest but are mostly blocked by stratospheric ozone. UV-B and UV-A are only partially blocked, and so are a risk for animals living on the surface. A decrease in stratospheric ozone will allow more of this damaging UV radiation to reach Earth’s surface.

34. Ozone Depletion is Linked to Climate Change Chlorofluorocarbons, nitrous oxide, and other gases linked to ozone depletion are also GHGs, and so they are contributing to global warming